Vibration instrument for bone



Jan. 7, 1936.

F. w. KRANZ VIBRATION INSTRUMENTFOR BONE AUDITION Original Filed March 29, 1923 INVENTOR TTORNEY seamed Jan. 7,1936 I Re. 19,808

UNITED STATES PATENT OFFICE VIBRATION INSTRUMENT FOR BONE AUDITION Frederick'W. mm, Fort Wayne, Ind assignor,

by mesne assignments, to Sonotone Corporagoni New York, N. Y., a corporation of New or I Original No. 1,540,783, dated June 9, 1925, Serial No. 628,683, March 29, 1923. Application for reissue July l, 1933, Serial No. 678,699

1 Claim. (Cl. 179-101) 'This invention relates to bone vibrators by winding l3 supplied with direct current; the cenwhich a person who is deaf or partially deaf to ortral member It may be a permanent magnet. dinary air vibration may be made to hear by A diaphragm bar ll of any elastic non-magmeans of vibrations conducted through his bones. netic material, such as brass or hard rubber 01' An object of the present invention is to prothe like, is secured across the core Hi above the 5 duce an instrument for use in the investigation air gap, spaced away from the magnetic core ill of the hearing through the bones by persons who by spacer blocks ii of nch-magnetic material.

are deaf to ordinary air vibration. The instru- In the center of its under face the bar l4 carries ment, however, can also be used to investigate a spool l6 extending down into the air gap. This bone audition in cases where the air audition is p l i f n n-m neti mater l u h a por normal. lain, hard rubber, or the'like. Preferably also it It is a further object of this invention to prois of insulating material in order that Foucault vide an instrument of the sort indicated which currents may not be created therein.

will itself produce very little vibration in the air, An actuating coil I8 is held in place upon this so that it is available for investigationsof the sort spool by flanges l9 and 20, and extends into the just mentioned and also for investigations of the gap around the upper end of the central core hearing of lower animals, fish and the like. member H 0 t ma n ti Co "I- It is a further object of the invention to pro- As illustrated, the upper end of the hollow in vide an instrument by which alternating electric the spool is closed to make a solid floor for concurrent either of a constant period or of the nectlon with the bar M. It will, however, be obcharacter of the usual telephone currents may V101 that y method for eelmeeting the 511001 'be translated into mechanical vibrations which to the bar may be used.

can be transmitted through th bones of a, per- To the center of the upper surface of the bar ll son to his hearing nerves. opposite the middle of the spool I6, is secured a It is a further object of this invention to prorod II which supports a disk 22, preferably of vide instruments of the kind indicated which hard ru r. i Order t it y be pressed shall produce vibrations of small amplitude but Il n t th b Structure Of DerSOll t W large force.- hearingis to be imparted, withoutdiscomfort; It is a further object of the invention to prooscillatory current is supplied to coil Iii through. vide an instrument of the sort indicated whose flexible leads 23 not interferin w t the motion efficiency will not be materially diminished by of the coil i8. I

pressing the instrument against the person of the In usi 8 the form the bone Vibrato! Shown subject. in Figures 1 to 3, sound-frequency current oscil- Other and further important objects of this lations are passed by leads 2! through winding invention willbe apparent from the disclosures in 011 l. T is e y current y be of the specification and the accompanying drawing, constant freq n y h 88 w d be ain d in which from a vacuum tube oscillator, and the frequency Figure 1 is a top plan view of a vibrator of one y be -l in the usual Way y Variable form of my invention. condensers or inductances. The current for coil Figure 21s a side view, partially in section, of II may also be supplied by the receiving set of 40 the vibrator or Figure l. a wireless telephone outfit, or from the re- Figure 3 is af'sectional view alo g line 3-4 of ceiving instrument of an ordinary telephone line. Figure 2. The current omillations for coil l8 may further Figure 4 is a central section of a vibrator of anbe suppli fr the ph ne of a telephone other form of theinvention. receiving device such as is frequently used in out- Figure 5 is an end view of the vibrator form fits for enabling deaf people tqhear. shown in Fig. 4. Any form of sound-frequency current may be The vibrator instrument shown in Figures 1 used for coil I. no matter what sort of apparatus to 3 includes an iron core ll having a central core is needed to produce this alternating current. member II and lateral pole pieces i! which ex- The alternating current flowing in coil III will 0 tend toward the end portion of said central core under the action of the magnetic field produced member and are spaced therefrom by asmall air in the surrounding gap by the exciting coil II gap. The central core member ll carries awindor by the permanent magnetism 'of core it, imim II which is supplied with direct current in partstrong up and down impulses to the coil ll .v/ any convenient-way. If desired, insteadof the andthusexertathrust iirstupandthen down iastened by screws against the bar H which will be transmitted through the rod 2| to the disk 22, imparting to it a vibratory movement corresponding to the impressed oscillatory currents. v

By pressing the contact surface of disk 22 against the mastoid bone, the teeth or other sound conducting bone portion of a hearer's person, these vibrations ofv the bar l4 are transi'erred to the bonewstructure of the heater and therethrough to the internal ear, inducing therein corresponding hearing sensations. Because of the narrow shape or the bar H, the vibrating system has but little surface in contact with the air. Very little vibration in the air itself will therefore be set up. For this reason, when the instrument is used in connection with a telephone receiving device and,a microphone such as are frequently used in outfits for enabling deaf people to hear, the tendency of the outfit to sing or how].

ill be much less than with such outfits as heretore made.

In the form or the vibrator device illustrated in Figures 4 and 5, a permanent magnet 29 has pole pieces 30 surrounded by windings 3|. These windings and the permanent' magnet core are enclosed within ,a casing 32 01 hard rubber or the like, and leads from the windings 3| are brought out of the casing as shown at 33; all of this structure being closely. similar to that of the usual telephone receiver. Instead bi a diaphragm, as in the vusual telephone receiver, a diaphragm bar 34 of magnetic material is placed across the open end 01 the casing 32 in close proximity to the pole pieces of the magnet 29. To the center 01' the bar 34 is connected by a rod 2| a disk 22, of hard rubber or like material, to be pressed against the bone structure ofa person to whom hearing is to be imparted. This bar is made of a thickness considerably greater than that of a telephone diaphragm, in order that when the contact surface of disk 22 of bar 34 is pressed against the bone structure of the bearer, the distance from the bar 34 to the pole pieces 3| shall be altered only slightly. The bar is firmly secured in place in any desired manner; for example, it may be 35 to a. ring 36 and the ring screw-threaded onto the casing 32. This permits adjustment of the bar to bring it into closeproximity to the pole pieces.

The vibrator shown in Figures 4 and 5 has a magnetic core structure of a standard telephone receiver for producing a permenent magnetic flux which flows through the core 23 passing over the magnet bar and the gaps from one pole piece to the other. To operate the device, electric sound-frequency current oscillations are sent through the windings 3| around the pole pieces, causing variations of the magnetic field in the gaps between the faces of the pole pieces 30 and the bar. These variations oi the magnetic field causes variations of the attraction exerted by the core on the elastic bar, and impart to th'ebar vitranslating sound-frequency alternating currents transmitting hearing-inducing vibratory forces 50 'to said bone structure, the stiffness of said diabrations corresponding to the supplied current oscillations. The vibrations are transmitted from the bar 34 over contact disk 22 to the bone structure of the hearers body and induce hearing in his internal hearing organs.

In pressing against the person of the hearer, the bar 34 will be slightly deflected toward the pole pieces ot'the magnet core 29, but the bar is made of sufficient thickness so that this deflection is not large enough to change the emciency or the i instrument. This rigidity of the vibrating member allows the air gap between it and the magnetic pole pieces to be made small, with a consequent gain in the amount 01' force exerted on the vibrating member. i vAs a result the stiff diaphragm bar vibrates with large forces and small amplitudes and is able to impart to the bone structure of the user the vibratory energy required to induce satisfactory hearing;

I am aware that numerous details oi construction may be varied through a wide range without departing from the principles of this invention. and I therefore do not p rpose limiting the patent granted otherwise than necessitated bywthe prior art.

I claim as my invention:

In a bone audition vibrating apparatus for into hearing-inducing mechanical vibrations imparted to hearing-inducing bone structure of a person, a magnetic core structure having a pole race for producing a continuous magnetic neld flux concentrated in an air space adjoining said pole face, an elastic diaphragm bar having an intermediate portion disposed adJacent said pole face, means for clamping the ends of said diaphragm bar on the opposite sides of the intermediate portion thereof relatively to said core structure, means including windings for applying 4 sound-frequency alternating currents to produce in combination with the'fiuxin the air space adjoining said pole i'ace corresponding vibratory i'orces imparting vibrations to the intermediate portion or said diaphragm bar, and contact means 45 actuated by the intermediate portion 01' said diaphragm bar for mechanically coupling the intermediate portion of said diaphragm bar to hearing-inducing bone structure 01 a person and phragm bar being sufllciently large and the area of said diaphragm bar in contact with the air being suillciently small to minimize to a negligible value the vibrations oi the air caused by said vibrations while imparting with said vibrations to said bone structure sound vibrations 01' small amplitude and large i'orce inducing by bone conduction audible sound in the internal ear organs of m the person. I

FRED. W. KRANZ. 

